A brand new UO research confirms what earth scientists have lengthy suspected: Crops first appeared on land about 460 million years in the past, in the midst of a 45-million-year-long geologic interval often called the Ordovician.
|Artist conception of early land vegetation within the Ordovician interval
[Credit: University of Oregon]
Authored by geologist Greg Retallack and revealed in The Palaeobotanist, the research describes a collection of plant impressions in an Ordovician rock deposit from Douglas Dam in Tennessee. Whereas earlier research have revealed fossil proof of invertebrate animals within the deposit, Retallack’s is the primary to determine entire fossil vegetation, together with mosses, liverworts and lichens.
Retallack, director of the Condon Fossil Assortment on the Museum of Pure and Cultural Historical past, mentioned these whole-plant impressions supply a key assist to Ordovician land plant theories.
“Fossil spores liberated from rocks have indicated a probable presence of nonvascular vegetation like these, and soil evaluation and carbon isotope research have all pointed to the doubtless presence of land vegetation throughout this era, however that is the primary line of direct proof,” he mentioned.
If land vegetation emerged and proliferated 460 million years in the past, they could have immediately contributed to a lower in atmospheric carbon dioxide and, in flip, to the worldwide cooling that fueled an explosion of latest marine life through the Ordovician and finally ushered an ice age that occurred about 445 million years in the past.
The deposit below research, comprised of rocks fashioned when most of Earth’s land mass was mixed into the supercontinent Gondwana, was eliminated when Douglas Dam was constructed for the Tennessee Valley Authority in 1942. Sections of the deposit have since been preserved on the College of Cincinnati and the Smithsonian Establishment, the place Retallack performed components of the research.
“It is one other instance of how dusty outdated museum collections can produce actually extraordinary new finds,” he mentioned.
One of many newly recognized fossil moss species, Dollyphyton boucotii, has been named for legendary singer Dolly Parton, whose Dollywood theme park is positioned a couple of miles away from the unique rock deposit.
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